Wave-guide system



Aprifl E. A: JONES 2,881,398

WAVE-GUIDE SYSTEM Filed May 14, 1953 Fems's 71A. zfowas United States PatentOfiice 2,881,398 Patented Apr. 7, 1959 WAVE-GUIDE SYSTEM Ernest A. Jones, Columbus, Ohio, assignor to Thompson Products, Inc., Cleveland, Ohio, a corporation of Ohio Application May 14, 1953, Serial No. 354,984

3 Claims. (Cl. 333-41) This invention relates to a wave-guide system and more particularly to a wave-guide system in which waves of two different polarizations may be selectively transmitted and simultaneously received through a common antenna and guide.

According to this invention, a round wave guide section, which is adapted for transmission of two plane polarized electromagnetic waves disposed at right angles to each other, is connected through a rectangular waveguide to a transmitter and receiver combination and is connected through a second rectangular guide to a sec ond receiver, the first rectangular guide being arranged to couple one plane polarized wave and the second rectangular guide being arranged to couple the other plane polarized wave. The first round wave-guide section is connected to a second round wave-guide section through phase shifter means arranged to change one of the plane polarized waves to a right-hand circularly polarized wave by shifting the phase of one of two right-angularly disposed components of the wave relative to the other or arranged to change the other of the plane polarized waves to a left-hand circularly polarized wave. The second wave-guide section may be coupled directly to an antenna which is adapted to radiate circularly polarized waves. The first receiver will receive waves which are either right-hand or left-hand circularly polarized while the second receiver will receive waves polarized in the opposite direction.

If desired, the second round wave-guide section may be coupled to the antenna through a second phase shifter means arranged to change a right-hand circularly polarized wave to a plane wave polarized in one direction and simultaneously change a left-hand circularly polarized wave to a plane wave polarized in a direction at right angles to said one direction. With this feature, the first receiver will respond to waves polarized in one direction while the second receiver will respond to waves polarized in a direction at right angles to said one direction.

According to an important feature of the invention, the first phase shifter means is selectively adjustable between a first position in which the plane-polarized wave coupled to the first rectangular guide is changed to a right-hand circularly polarized wave in the second round wave-guide section and a second position in which the wave coupled to the first rectangular guide is changed to a left-hand circularly polarized wave in the second round wave guide section, the wave coupled to the second rectangular guide being reversed from left-hand to right-hand circularly polarized waves in a similar manner. By this feature, the direction of polarization of the waves radiated or received by the antenna is reversed with respect to the receivers.

It will be apparent that this wave-guide system has a great variety of advantageous applications such as, for example, in radar systems in which one receiver may respond to waves polarized in one direction while the other receiver will respond to waves polarized in the opposite direction.

An object of this invention, accordingly, is to provide an improved wave-guide system in which waves polarized in opposite directions may be received or transmitted separately.

Another object of the invention is to provide a waveguide system in which right-hand or left-hand circularly polarized waves are transmitted and both polarizations are received simultaneously.

This invention contemplates other objects, features and advantages which will become more fully apparent from the following detailed description taken in conjunction with the accompanying drawing which illustrates a preferred embodiment and in which the single figure illustrates a wave guide system embodying the principles of the present invention.

Reference numeral 10 designates a round wave-guide section which, of course, is adapted for transmission of two plane polarized electromagnetic waves disposed at right angles to each other. One of these plane polarized waves is coupled through a rectangular wave-guide 11 to a transmitter 12 and a receiver 13. The transmitter 12 and the receiver 13 may be arranged to transmit and receive radar pulses with switching devices 14 and 15, such as gas tubes of a conventional radar duplexer arrangement.

The other of the right-angularly disposed plane polarized waves in the round wave-guide section 10 is coupled through an impedence transformer 16 and a rectangular wave-guide 17 to a second receiver 18. Thus the first receiver 13 will respond to plane polarized waves of one direction in the round wave-guide section 10 while the second receiver 18 will respond to waves that are plane polarized in a direction at right angles to said one direction.

The round wave-guide section 10 is coupled through a first phase shifter generally designated by reference numin the first round wave-guide section 10 to a left-hand rection of polarization with respect to the plane polarized wave coupled to the rectangular guide 17.

For these purposes, the phase shifter 19 may prefer-' ably take the form as illustrated in the drawing. A round wave-guide section 22 preferably having the same diameter as the round wave-guide sections 10 and 20 is disposed therebetween and rotatable about its axis. To allow this rotation with a minimum of energy loss at the junctions between the guide section 22 and the guide sections 10 and 20, a pair of choke joints 23 and 24 are provided. A quarter-wave plate 25 projects radially inwardly from the inner surface of the round guide section 22 and is movable, by rotation of the guide 22 about its axis, between a first position as illustrated in full lines and a second position as illustrated in 3...: brokfi l a t e two positions, being 90 apart and the quarter-wave plate, in each position, projecting at an angle of 45 relative to the plane polarized Wave in the round guide section 10 which. is coupled to. the rectangular guide 11 and hence at an angleof 45 relative,

to, the plane polarized wave coupled; to. the. rectangular guide 17, the two plane polarized wavesbeing at right wave in the round wave-guide section 10. may be shifted.

90, in phase so that the. plane polarized wave willbe transformed entirely into a circularly polarized wave in the second round wave-guide. section 20. The oper-. ation of'thequarter-wave plate 25 is, of'course, reversible so that a circularly polarized. wave inthe round guide section 20, will be transformed into a plane polarized wave in the first, guide section 10, the plane of polariza-v tion of the resultant wave. in. the first guidesection 10. being dependent uponwhether the circularly polarized wave in the second section 20 is right or left hand polarized and dependentupon whether the quarter-wave plate is in the full line position or the dotted line position.

Itwill thus be apparent that one. of. the rectangular waye guides. 1-1 and 17' may becoupledto a right-hand circular. polarizationat: the. antenna while the other rectangular, guide, is coupled to, a. leftehand: circular polarization at the antenna.

The wave-guide system of this invention may preferably be. such that the rectangular-guide- 11 may be coupled to-a plane polarized: wave. of. one: directionat the antenna 21:.while the rectangular guide 17 coupledtoa planepolarized: wave. of a direction at right angles relativeto said one. direction. For this purpose, a secondphase shifter. may. be .providedinthe round wave-guide section 20; This phase. shifter. may preferably comprise. a quarter-wave plate 26 havingan operation-like thatof the: quarter-waveplate 25:.as described indetailabove.

Itwill be understood that the-phase-shiftersmay take other forms and that other. modificationsandzvariationsmaybe effected: without departing from the spirit and scopeofthe novel concepts: of the presentinvention.

I: claim-as my invention: 1. In a wave-guide system, a first roundwave-guide section adapted for transmission of two plane polarized electromagnetic waves disposed: at. rightangles toeach other, first! coupling. means for coupling one of said wayes;to a.transmitter andia first receiver, second coupl ng meansfor coupling the other ofsaid waves toa second-:- receiver, a. second round wave-guide section arranged to transmit circularly polarized waves, first phase shifter means betweentsaid wave-guide sections arranged to selectively shift thephase of one of two equal right-angularly disposed components of "a wave- By proper dimensioning of the quarter-v either one=quarter wave length ahead. or oneaquarter wave length behind, and second phase shifter means arranged to couple said second wave-guide section to an antenna and arranged to shift the phase of one of two equal right-angularly disposed components by onequarter wave length.

2. In a wave-guide system, a transmitter, first and second receivers, a first'round wave-guide section adapted for transmission of two plane polarized electromagnetic waves disposed'at right anglesito each other, a first rec tangular guide for coupling one of said waves" to said transmitter and to'said first receiver, a secondrectangular guide for coupling the other of said waves to said second receiver, a second round wave-guide section adapted to transmit circularly polarized waves, phase shifter means between said first and second round Waveguide sections arranged to change one of said plane polarizedwaves to a right-hand circularly polarized wave and vice versa' and arrangedtochange the other Ofsaid-WaVes toa left-hand circularly polarized wave and-vice versa; an antenna adapted-to radiate circularly polarized-waves,

a third round wave-guide section coupling. said second wave-guide section to said. antenna, and second phase shiftenmeans in said third'round wave-guide section arranged to changea right-hand circularly polarized wave to a wave-in-one-plane.and'arranged-to change a lefthand'circular-ly polarized wave to a wave inthe plane at adapted to transmit circularly polarized waves; phase shifter-means between said first and secondround waveguide sections arranged to change one ofsaid plane polarized waves to a right-hand circularly polarized wave andvice versa and arranged to change the other offsaid' Waves-toe left-hand circularly polarized wave and vice versa, an antenna adapted to radiate circularly polarized waves, a third round wave-guide section coupling said second wave-guide section to said antenna, and'esecond phase shifter means in said third round wave-guide section arranged'to change a right-hand circularly polarized wave to a wave in one plane and arrange tochange a left-hand circularly, polarized wave to a wave. in the plane at right angles to,said one plane, saidfirst'phase shifter means beingselectively movable between a first position in which the wave coupled to said firstrecg tangular guide is changed to a right-hand; circularly polarized wave in said second round wave-guide section and a secondposition in which the wave coupled tosaid} first rectangular guide is changed to a left-hand circularly polarized-wave in said second round wave-guide section.

References Cited in the file of 'this patent UNITED STATES. PATENTS;

2,606,248 Dicke Aug. 5, 19-52 2,607,849 Purcell- Aug. 19, -2 2,713,151: Farr: July- 12, 1955 

